All organisms in the Kingdom Plantae are multicellular, which means that each organism is comprised of more than one cell. Being multicellular allows plants to grow large and complex, since the cells can differentiate and serve various different functions for the plant.
In addition to multicellularity, all plants share several other characteristics. They are capable of making their own food through a process called photosynthesis, which involves absorbing light energy from the sun and converting it to chemical energy stored in carbohydrates. All plant cells have cell walls comprised of a carbohydrate material called cellulose, and they have the ability to grow larger through cell division. Plants lack motility. They reproduce both sexually and asexually.
Plants are divided into four main phyla based on shared characteristics.
The Phylum Bryophyta contains plants, such as mosses and liverworts, which lack vascular tissue that other plants use to transport water and nutrients. The Phylum Pteridophytae contains plants, such as horsetails and ferns, which have vascular tissue but do not reproduce with seeds. Most plants belong to either the Phylum Angiosperm or Phylum Gymnosperm. Phylum Angiosperm contains flowering plants, such as sunflowers and apple trees, which reproduce with developed seeds. Phylum Gymnosperm includes palm trees and other nonflowering plants that reproduce with undeveloped, primitive seeds.